Vascular endothelial growth factor (VEGF) is known to play a critical role in vasculogenesis and angiogenesis of the developmental process (Soker S et al., J Cell Biochem. 85:357-368, 2002). As it has been reported that VEGFR1 is overexpressed not only in vascular endothelial cells, but also in colonic and pancreatic cancer cells, and is directly involved in tumor progression and metastasis, VEGFR1 is considered to play an important role in angiogenesis, tumor growth and metastasis, inflammation, etc (Wey J S et al., Cancer 104:427-438, 2005; Fan F et al., Oncogene 24:2647-2653, 2005). VEGF is one of the most important factors in tumor angiogenesis, is expressed in most tumor tissues, such as renal cell cancer (Tomisawa M et al., Eur J Cancer 35:133-137, 1999), lung cancer (Volm M et al., Int J Cancer 74: 64-68, 1997), breast cancer (Yoshiji H et al., Cancer Res. 56:2013-2016, 1996), ovarian cancer (Sowter H M et al., Lab Invest. 77:607-614, 1997), etc., and is secreted not only in tumor cells, but also in tumor stromal cells. Although mouse anti-human VEGF monoclonal antibodies did not have much effect on the ex vivo growth of tumor cells in an attempt to use VEGF antagonists to inhibit tumor growth, the antibodies showed significant inhibiting effects for tumor angiogenesis and tumor growth in vivo (Kim K J et al., Nature 362: 841-844, 1993; Borgstrom P et al., Cancer Res. 56:4032-4039).
It is widely known that VEGF is strongly associated with not only tumors, but also other diseases, and various efforts have been made to develop therapeutics for these diseases.
Representative examples of these diseases include rheumatoid arthritis (RA) which is a disease associated with angiogenesis, diabetic retinopathy, ischemic retinopathy, psoriasis, etc., and it has been revealed that VEGF functions as an important factor to theses diseases. In the case of RA, it was confirmed that the amount of serum VEGF from RA patients increased compared to that from patients in a control group (Ikeda M et al., J pathol. 191:426-33, 2000). The amount of serum VEGF from diabetic patients also increased and the increased blood sugar level caused toxic effects on the endothelium to induce a hyperglycemic pseudo-hypoxic state which induced VEGF production. This showed a correlation between endothelial damage in diabetes and dysfunction (Lim H S et al., Diabetes Care 27:2918-24; 2004). Excessive secretion of VEGF in the retina causes ocular neovascularization and hematoma, resulting in visual impairment/blindness. In an effort to prevent visual loss associated with proliferative diabetic retinopathy (PDR) and diabetic macular edema and avoid side effects associated with destructive treatments such as laser treatment, humanized monoclonal anti-VEGF antibody fragments which are selectively bound to all the subtypes of VEGF are used. The compound known as rhuFab V2, produced by Genetech Co., Ltd. is now under clinical research and known to show some effectiveness in prevention of PDR or diabetic macular edema (Heier J S, Program and abstracts of the American Academy of Opthalmology 2002 Annual Meeting; October 20-23, Orlando, Fla.).
Various types of 40 or more angiogenesis inhibitors are currently under clinical development for various kinds of tumors. VEGF and VEGF receptors are the most representative targets, and include agents which inhibit activity, signal transduction, and production. VEGF inhibitors include antibodies, aqueous VEGF receptors (VEGF traps), etc. Because bevacizumab (Avastin™, Genetech), which is a humanized anti-VEGF monoclonal antibody as an angiogenesis inhibitor for tumor treatment, showed life-prolonging effects on patients with metastatic colorectal cancer, the drug was approved by the FDA in February, 2004. Therefore, the development of these anti-VEGF human monoclonal antibodies has advantages in that the antibodies are a promising candidate for treatment of angiogenesis and various diseases associated with it and may be used in clinical and preclinical settings due to their minimal side effects, and thus the development of various therapeutic agents using these antibodies warrants due attention.
Thus, the present inventors have selected 14 kinds of human antibodies specifically bound to VEGF, confirmed that the human antibodies have binding and neutralizing capacities similar to those of Avastin™ and exhibit cross reactivity with the mouse VEGF, proposed that the human antibodies of the present invention may be effectively used in treatment of VEGF-overexpressed diseases, and have made the present invention.